Where existing electrical socket connections are not provided, for example during building construction or construction in remote places, it is necessary to tap into an existing electrical power cable using a power line connector or tap splice. Examples of power line connectors/tap splices are known in the prior art, and are discussed below.
It is a problem in some of this art to provide a water-tight seal when tapping into an electrical power cable with a tap.
It is additionally a problem in some of the art to provide a tap which can be assembled with an electrical power cable without the need for insulating blankets or high voltage gloves.
Further, it is a problem in some of the art to provide a tap assembly which, when removed from the electrical power cable, requires little effort to securely repair the electrical power cable.
A hot-line connector is shown in U.S. Pat. No. 3,668,609 issued to Edwin A. Link. According to this patent, a cable connector is sealingly engaged around the outside of an insulated electrical power cable. The cable connector includes a tubular extension with a guide passage extending perpendicularly to the electrical power cable. An electrically conductive tap is crimped to a cable lead, has a pointed tip portion, and is received in the guide passage of the tubular extension. A manually-operable threaded drive assembly has a cup-shaped portion for receiving the electrically conductive tap, and has an aperture receiving a collet or split ring through which the cable lead can pass. The collet has a tapered surface receiving a washer which, when assembled with the electrically conductive tap, bears against an end of the tap. The tubular extension has an externally threaded portion which supports the manually-operable threaded drive assembly. Rotation of the manually-operable threaded drive assembly causes the collet to force the pointed tip of the electrically conductive tap through the cable insulation and into electrical contact with the electrically conductive members in the cable.
However, in U.S. Pat. No. 3,668,609 the assembly of the manually-operable threaded drive assembly, in forcing the electrically conductive tap into the cable, does not produce a sealing effect with the electrically conductive tap by the insulator body sealing around or deforming of the insulation of the electrical power cable. The sealing is by other means, however.
An electric wire connector with insulation piercing means is shown in U.S. Pat. No. 3,585,571 issued to Raymond G. Davis. In this device, a block of insulating material has two grooves for receiving main electrical power cable wires. First and second bores in the block communicate respectively with the two grooves. The bores are substantially identical. The first bore receives at one end thereof a bolt or screw. An electrically conductive tap is loosely received in a portion of the first bore, and has a head which can be urged by the bolt or screw into the electrical power cable. An electrical lead disposed between the head of the electrically conductive tap and the end of the bolt or screw, so that it remains in electrical contact with the electrically conductive tap. The bolt or screw must be composed of insulating material.
However, in the above-discussed U.S. Pat. No. 3,585,571, there is no insulation at the point of penetration of the electrically conductive tap into the electrical power cable. Furthermore, a water-tight connection is not formed by the assembly of this patent. Additionally, if the bolt or screw works loose, electrical connection can be lost between the electrical lead wire and the electrically conductive tap, and water can penetrate to the electrically conductive tap. Further, the assembly is not adapted for use with a variety of types of insulated electrical power cables such as loosely woven or tightly woven electrical power cables. Also, in forcing the electrically conductive tap into the cable, the assembly does not produce a sealing effect with the electrically conductive tap by the insulator body sealing around or deforming the insulation of the electrical power cable.
A cup-shaped underground tap connector is shown in U.S. Pat. No. 4,050,761 issued to Robert V. De France. The connector has a piercing member and a clamping assembly for bringing the piercing member into tight engagement with an electrical power cable. The clamping assembly includes a top plate and a bottom plate arranged on opposite sides of the electrical power cable, and are tightened together by a pair of threaded bolts or screws. The top plate has an aperture receiving a body which carries the piercing member and an electrical lead wire. The electrical lead wire is connected to the body by a pair of set screws. A disc-like sealing pad is disposed at the point of contact of the electrical power cable and the body carrying the piercing member, and the piercing member extends through the sealing pad.
However, in the above-discussed U.S. Pat. No. 4,050,761, the assembly, in forcing the electrically conductive tap into the cable, does not produce a sealing effect with the electrically conductive tap by the insulator body sealing around or deforming the insulation of the electrical power cable.
In U.S. Pat. No. 3,461,419, a hot line connector is shown which includes a cable tap having a penetrating needle, and a clamping assembly having a portion which supports and guides the cable tap. The clamping assembly is formed by two mating parts having undulating mating surfaces. The portion which supports and guides the cable tap includes a housing having an insulator at one end, the insulator including hinged overlapping sections forming a passage for the cable tap. The cable tap is connected fixedly to an electrical lead wire, and is carried by a support member having a beveled end. A threaded collar member is engageable with the housing, and bears against a washer. The washer in turn bears against a flange, which in turn bears against the beveled end of the support member carrying the cable tap. Manual rotation of the threaded collar member forces the pointed end of the cable tap through the insulation of the electrical power cable. It seals by other means, however.
However, in U.S. Pat. No. 3,461,419 the cable tap assembly is fixedly connected to the electrical lead cable, has a fixed penetration depth due to the shape of tip, and is not adapted for use with a variety of types of insulated electrical power cables such as loosely woven or tightly woven electrical power cables. Furthermore, in this patent the assembly of the manually-operable threaded drive assembly, in forcing the electrically conductive tap into the cable, does not produce a sealing effect with the electrically conductive tap by deformation of the insulation of the electrical power cable.
An electric test clamp is shown in U.S. Pat. No. 3,094,366 issued to J. R. Harmon, Jr. This device includes a main body member attached by a band to an electrical power cable. The main body member has a threaded passage for receiving a threaded member carrying a pointed cable tap. The main body member also has a hollow interior with a spring member therein for urging a movable plate against a bottom portion of the main body member. An electrical lead wire is connected atop the main body, and is retained there by the head of the cable tap. The electrical lead wire is thereby left exposed.
However, in U.S. Pat. No. 3,094,366, the cable tap assembly is electrically exposed, and the head of the cable tap is electrically exposed. Also, the cable tap has a limited depth to which it can be inserted into the electrical power cable due to the presence of the head of the cable tap, and is therefore not adapted for use with a variety of types of insulated electrical power cables such as loosely woven or tightly woven electrical power cables. Furthermore, a water-tight connection is not formed by the assembly according to this patent. Also, during assembly, high voltage gloves should be worn since conductive portions remain exposed and would be dangerous whether or not wet.